This project aims to develop chemical methods that correctly identify and partition the nutritive and nonnutritive matter of food. Digestion experiments and mathematical methods will be used to test the newly developed and traditional chemical components for uniform true digestibility with various classes of foods and species of laboratory animals including man. Out of these tests a new system for partitioning the nutritive matter of foods will be developed that will properly separate the nonnutritive matter from the nutritive matter. Regression equations will be developed to predict nutrient utilization from chemical composition for the various species of animals and to estimate digestible energy from nutritive matter (new system); nutritive matter from total digestible nutrients (old system); and, digestible energy from total digestible nutrients. When the above objectives are completed, samples of foods produced in various regions of the country will be collected and analyzed by the newly developed chemical methods. The results will be published in appropriate scientific journals and tables of food composition and utilization.